Chemical heating pad



April 11, 1939. MARKEL ET AL 2,153,670

CHEMICAL HEATiNG PAD Filed Jan. 17, 1938 FIE E INVENTORS L EON MHEHEL FEEDER/Cid L EEYNOL 05 BY ATTORNEY.

Patented Apr. 11, 1939 U ITED STATES 2,153,670 CHEMICAL HEATING PAD Leon Markel, San Francisco, and Frederick L.

Reynolds, Mill Valley,

United States Appliance mesne assignments, t

Calm, assignors, by

Corporation, San Francisco, Calif., a corporation of California Application January 17, 1938, Serial No. 185,416

4 Claims.

This application relates generally to chemical heating pads of the type useful for permanent hair waving operations.

Conventional chemical heating pads, such as used for permanent hair waving operations, make use of a dry chemical mix adapted to be moistened with water, to initiate an exothermic reaction. Generally the chemicals are carried within a foil envelope, one perforated side of In which is contacted with a sheet of absorbent material saturated with water. A predetermined amount of moisture is thereby permitted to penetrate through the perforations, to be absorbed by the chemical and by an absorbent diluent like 15 talc or diatomaceous earth, which is usually provided,

It has been found that in manufacturing and marketing pads of the above character, there is a relatively high percentage of rejects, represent- 20 ing pads which do not properly heat when moistened. The percentage of rejects can be reduced by furnishing the pads in sealed metal containers, but this adds considerably to cost, and does not entirely alleviate the difliculty.

In a typical instance a pad of the above character will consist of metallic aluminum, copper oxide or copper carbonate, sodium or potassium chlorate, and salts likealuminum chloride or aluminum sulphate. I have found that even though such a chemical mix is in ostensibly dry condition, some chemical action may take place, which tends to render the pad relatively inactive when moistened with water. This may be true notwithstanding the fact that the chemical ac- 35 tion taking place before moisture is applied, may

not consume the metallic aluminum or other chemicals to any material degree. Such premature chemical reaction is probably made possible because of small amountsof moisture present,

40 and to a tendency towards hygroscopicity, particularly whensalts like aluminum chloride or aluminum sulphate, are present.

This invention has for its primary object the production of a chemical pad suitable for permanent hair waving operations, which will not de teriorate even when exposed to the atmosphere, and which can always be relied upon to afford the desired heating operation.

Further objects of the invention wilLappear from the following description in which the preferred embodiment of the invention has been set forth in detail in conjunction with the accompanying drawing.

55 Referring to the drawing:

Fig. 1 isa perspective view showing a chemical pad for use in accordance with the present inventlon.

Fig. 2 is a side elevational view of the pad to shown in Fig. 1.

when moistened with water.

Fig. 3 is an enlarged cross-sectional detail, showing the pad applied to wound hair.

Fig. 4 is a side elevational view showing the pad together with a protector and curler assembly. G

In experimenting with various chemical mixtures and compounds, we have found that mixtures such as metallic aluminum and copper oxide, or metallic aluminum and copper carbonate,

or the foregoing together with sodium or potassium chlorate, are stable and inert, and will not react when exposed to the atmosphere, or even This is because relatively insoluble copper compounds like copper oxide or copper carbonate, will not ionize in the presence of water, and therefore no copper ions are afforded for replacement by aluminum. We have also found that other chemicals capable of activating such a dry mix, can be made up in the form of a stable innocuous solution, but application at the time'the pad'is to be used.

The present invention can be best understood after a description of the conventional type of chemical pad illustrated in the drawing. Thus the pad consists of an envelope l0, made of a suitable metal foil like tin foil, which has attached to it a flap or sheet ll of absorbent material, such as flannel or soft paper fiber. The envelope l0 contains the dry chemical mix I2, capable of exothermic reaction. One side of the foil envelope i0 is adapted to be provided with the perforations l3. In the conventional types of pads previously described, an operator forms the perforations l3 by some suitable instrument, after which the sheet I l is saturated with water, and the sheet superposed upon the'perforated side of the envelope ill, in the manner indicated in Fig. 2. The pad is then applied over a strand of wound hair, as for example upon a Croquignoie curler II as illustrated in Fig. 4, and is retained 40 in place by a small clip i6. Moisture from the sheet ll penetrates through the perforations l3 and is absorbed by the chemical mix II.

In the present invention we make use of a chemical solution for saturating the sheet H, whereby without this or an equivalent chemical solution, there would be no exothermic chemical reaction. In other words with our preferred pad a chemical saturating solution is a prerequisite to operation, and the moistening of sheet ll with plain water, will cause no reaction whatsoever'.

As representative of the dry chemical mix which we employ, reference is made to copper compounds like copper oxide and a copper carbonate like "malachite, which are relatively insoluble, and which of themselves do not electrolize in water. Such a copper compound is used together with metallic aluminum, such as aluminum in the form of granules. A suitable amount of sodium or potassium chlorate, which are effective depolarizers, is also provided. The proper 'proportioning of these ingredients will depend upon the particular requirements, and will be understood by those skilled in the art.

In addition to the above ingredients a suitable absorbent diluent is provided, such as talc or diatomaceous earth. Such an absorbent diluent or filler plays no part of itself in the chemical reaction, but merely serves as a. medium for absorbing chemical solution.

With the dry chemical mixes of the type described above, we make use of a chemical solution which will activate an exothermic reaction, such as a solution which is hydrolized to afford an acid component, or an ammonium radical. Particular reference can be made to solutions of acids like sulphuric, hydrochloric and acetic acid, and to salts of these acids such as aluminum chloride, aluminum sulphate, and like salts which hydrolize in solution to release their respective acids. As a group of compounds capable of affording an ammonium radical reference can be made to ammonia, and salts of ammonium and strong acids, such as ammonium chloride,'and ammonium sulphate. The dilute solutions of such chemicals are comparatively innocuous, and cause no serious injury to hair or to the skin. This is particularly true of salts like aluminum chloride or aluminum sulphate and ammoniacal solutions. In fact ammoniacal solutions are frequently applied to the hair, immediately preceding a permanent waving operation.

When using the acids or acid salt solutions referred to above, as for example a solution of aluminum chloride, the copper oxide or copper carbonate is in effect converted and electrolized to afford copper ions to be replaced by metallic aluminum. What probably takes place is that a salt like aluminum chloride converts copper oxide or copper carbonate to copper chloride, which then reacts with metallic aluminum to precipitate metallic copper. In any event such a chemical solution will activate the dry chemical mix, to carry out an effiicent exothermic reaction.

It will be apparent that the solution may contain various combinations of chemicals, instead of simple acids or salts as referred to above. For example a solution can contain both aluminum chloride and aluminum sulphate. Also it is possible to provide both an acid salt like aluminum chloride, and an ammoniacal salt like ammonium chloride.

Ammoniacal solutions probably operate in a somewhat different way than acids or acid salts.

Although the reactions may be complex, it is probable that the ammonium radical combines with the copper of the copper compound, to form a complex copper ammonium ion. In any event an ammoniacal solution serves to dissolve the copper compound, and to cause an exothermic reaction to take place, in which metallic copper is precipitated.

The advantages of our invention will be apparent. No unusual precautions needbe taken in order to prevent contact of the chemical pad to the atmosphere, before it is used. In fact one may dispense with the relatively expensive metal foil containers, and employ an envelope made of waxed or parchment paper. Even though some moisture from the atmosphere is absorbed no preliminary detrimental reaction takes place, and such pads can be relied upon to give a desired exothermic reaction when they are moistened with chemical solutions as previously described.

While it is preferable to employ relatively insoluble and stable compounds like copper oxide or copper carbonate, our invention can be applied to advantage with chemical pads employing relatively soluble compounds like copper'sulphateor copper chloride together with metallic aluminum and a depolarizer. Such pads are generally activated by moisture, but use of an ammoniacal moistening solution in place of plain water, will insure activation irrespective of previous exposure'to the atmosphere. Thus pads which fail to show activity when moistened with plain water, are made active by use of an ammoniacal solution.

It has been explained that many conventional pads contain copper oxide or copper carbonate, together with aluminum, a depolarizer, and a solvent for the copper oxide or carbonate, like aluminum sulphate or chloride. When such pads have been subject to preliminary deterioration, they can be activated by use of a chemical moistening solution of the kind described, such as an ammoniacal solution.

We claim:

'1. In means for permanent hair waving, an exothermic chemical heating element comprising a normally substantially insoluble copper compound in solid form together with metallic aluminum, and a solution for moistening said element atthe time the tion including a solvent for the copper compound.

2. In means for permanent hair waving, an exothermic chemical heating element adapted to be placed in heat transferring relationship with a strand of wound hair, said element comprising an ostensibly dry mix including a normally substantially insoluble copper compound, metallic aluminum, and a depolarizing salt, and a solution adapted to be supplied to said dry mix to make possible exothermic reaction, said solution including a solvent for the copper compound.

3. In means for carrying out heating operations in permanent hair waving, an exothermic chemical heating element adapted to be placed in heat transferring relationship with a wound strand of hair, said element comprising an ostensibly dry mix consisting of metallic aluminum, any one of a group of substantially insoluble copper compounds comprising copper oxide and copper carbonate, any one of a group of depolarizing agents comprising sodium chlorate and potassium chlorate, said dry mix of itself being incapable of exothermic reaction even though moistened, and a chemical solution for moistening said element consisting of water together with a chemical of that group consisting of acids and acid salts capable of affording an acid radical and ammoniacal compounds capable of affording an ammonium radical.

4. In means for carrying out permanent hair waving operations, an exothermic heating element adapted to be placed in heat transferring relationship with a wound strand of hair, said element comprising an ostensibly dry chemical mixture including metallic aluminum, a normally substantially insoluble copper compound, and a depolarizing agent, said chemical mixture being disposed within a retaining envelope having one perforated wall, and a sheet of absorbent material moistened with a solution containing a solvent for the copper compound, and disposed in contact with said perforated wall.

LEON MARKEL. FREDERICK L. REYNOLDS.

element is used, the solu- 

